*{
    padding: 0;
    margin: 0;
}
.sloth{
    margin: 0 auto;
    width: 247px;
    height: 194px;
    background: url(images/sloth.png) no-repeat;
    /*背景大小*/
    background-size: 400%;
    /* background-position: 100% 80%; */
    background-position: -741px -970px;
}
.info{
    margin: 0 auto;
    width: 247px;
    height: 30px;
    line-height: 30;
    font-size: 16px;
    text-indent: 0.5em;
    color: #fff;
    background: rgba(0,0,0,.8);
}
.btn_wrap{
    position: relative;
    margin: 15px auto 0;
    width: 246px;
    height: 246px;
    border: 1px solid #ECECEC;
    border-radius: 50%;
    box-sizing: border-box;
}
.btn_mask,.force_btn{
    position: absolute;
    top: 50%;
    left: 50%;
    width: 146px;
    height: 146px;
    background: #000;
    margin-left: -73px;
    margin-top: -73px;
    /* transform: translate(-50%,-50%);左右垂直居中 */
    border-radius: 50%;
    box-sizing: border-box;
}
.force_btn{
    padding: 0;
    background: #337ab7 url() no-repeat center center;
    background-size: 80px;
}
.btn_mask{
    background: rgba(51,122,183,0.5);
    transform: scale(1.0);
    transform-origin: center center;
    transition: all .1s;
}